Jerusalem,  The Pfizer-BioNTech Covid-19 vaccine is moderately less effective against the South African variant, suggests a study.

The findings, published in the journal Cell Host & Microbe, showed that the vaccine is effective against the original SARS-CoV-2 strain and the UK variant, but provides weakened protection against the South African variant and the combined UK-South African variants.

"Our findings show that future variants could necessitate a modified vaccine as the virus mutates to increase its infectivity," said researcher Ran Taubea from the Ben-Gurion University of the Negev in Israel.

For the study, the research team looked at the effectiveness of the vaccine against the original viral strain, the UK and the South African variants, as well as strains that harbour combined changes in the viral spike.

They are continuing to test other circulating variants as they constantly emerge with the hope to identify potentially risky mutations that can compromise the vaccine, the study indicated.

The research team also compared neutralising antibody levels following administration of one and two doses of the vaccine, as opposed to levels in patients that have recovered from Covid-19.A

The team found that vaccination provided optimal levels of protection, when compared to the lower levels of protection that were observed in recovered patients.

A recent study, published in the journal Nature, also indicated that Covid-19 vaccines developed by Moderna and Pfizer-BioNTech significantly appear less effective against the Covid variant that first emerged in South Africa.